1. Field of the Invention
The present invention relates to a method and apparatus for interpolating pixels, and more particularly, to a method and apparatus for interpolating pixels based on edge detection.
2. Description of the Prior Art
In conventional interlaced scanning, each frame is actually composed of two fields: an odd field composed of odd scan lines and an even field composed of even scan lines, wherein the odd field and the even field of the same frame are successively scanned. In a de-interlacing process, the two fields are combined into one frame and then the frame is sequentially scanned at double horizontal scan frequency so that the quality of the display image is improved.
An interpolation operation is commonly employed in the de-interlacing process. In U.S. Pat. No. 6,133,957, an interpolation method is disclosed. The disclosed interpolation method identifies a first pair of pixel sets and a second pair of pixel sets on opposite sides of the vertical direction of the location where an additional pixel would be interpolated. The method performs an ambiguousness test based on the first and second pair of pixel sets to determine a weight factor used for interpolating the additional pixel.
Another interpolation method is disclosed in U.S. Pat. No. 6,421,090. The disclosed method is used for video having at least two fields. The method calculates a motion value of successive frames and then interpolates pixels based on the motion value.
As mentioned above, the interpolation method of the prior art needs to perform a complex ambiguousness test with two pairs of pixel sets or perform motion estimation with at least two fields, and these operations increase the complexity of interpolation and the cost of circuit implementation.